Carrier for optically reproduceable film records and method of treating same



Dec. 22, 1942. o s-r ET AL CARRIER FOR OPTICALLY-REPRODUC'IBLE FILM RECORDS AND METHOD OF TREATING SAME Filed Feb. 27, 1941 f/VKMTOFS Calwclz's Johannes Dip val.

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Patented Dec. 22, 1 942 UNITED STATES PATENT OFFICE CARRIER FOR OPTICALLY REPRODUCE- ABLE FILM RECORDS AND DIETHOD OF TREATING SAME Gilles Holst' and Cornelis Johannes Dippel, Eindhoven, Netherlands; vested in the Alien Prop-. erty Custodian Application February 27, 1941, Serial No. 380,952 In the Netherlands January 5, 1940 7 Claims.

formed in a recording layer whose surroundings are provided with a suitable thin protective layer.

To the recording layer there is added oneor more substances which, in co-operation with one or more molecularly or colloidally dispersed substances which exist in the recording layer or which themselves form this layer, bring about colouring of the track by chemical reaction.

The expression colouring is to be understood to mean in general that after the abovementioned treatment the track substantially does not transmit the species of light used in reproduction or copying. The track need therefore not be blackoafter treatment but may exhibit that colour which does not transit the species of light used in'reproduction. v

After treatment according to the prior specification a band-shaped carrier or film is consequently obtained which comprises a protective layer and a recording layer, generally also a supporting layer, forexample of Celluloid, the track cut in the recording layer on the film being coloured relatively to the protective layer. It the sound track is recorded by means of a V- shaped chisel having a large apical angle the covering layer itself is also partly removed and will be cut away angularly at the edge of the said track. Although the harmful effect (lens effect) of refraction in the profile cut is substantially obviated according to the prior specification by the process hereinbefore described, small refractions which are harmful so far as reproduction is concerned nevertheless occur as a result of the angularly descending edge of the protective layer when the film is optically reproduced. a

According to the process of the invention, after the addition and chemical reaction of the substances which bring about colouring, the protective layer is removed so that only the film with recording layer comprising a coloured track,- and in some cases the supporting layer, remain for reproduction. Due to the removal of the protective layer the angularly ascending edge is eliminated so that the injurious refraction referred to hereinbefore can no longer occur. The removal of the protective layer may be effected for example chemically, it being possible for the film and its protective layer to be brought into 5 contact with a surface soaked with a solvent. As an alternative, the film may be passed through a chemical bath, containing a solvent which does not'attack the other layers.

If in the case of a record being made on the carrier it is desired to electro-optically play of! the record directly after recording this may be ensured by providing the carrier with a coloured protective layer in accordance with the invention. After playing of! the sound track is blackened and the protective layer isthen removed.

In order that the invention may be clearly understood and readily carried into effect it will now be described more fully with reference to the 2 accompanying drawing, in which prising three layers.

Fig. 2 is a sectional view of the carrier shown in Fig. 1 from which the protective layer has been removed.

The carrier of Fig. 1 comprises a supporting layer ID of Celluloid, a superposed recording layer ll of gelatine and a protective layer l2 of Celluloid lacquer. A sound track is cut in well-known manner in these layers by, means of a chisel hav- This cutting operation will have the effect of cutting away not only a part of the recording layer H but also a part I! of the protective layer with the result that angularly ascending edges I4 and I5 are formed in the latter layers.

For reproducing the sound track the carrier is treated with substances which, in co-operation with substances existing in the recording layer, bring about colouring of the track by chemical reaction, since due to the presence of the protective layer and thanks to the principle of the prior specification. viz. the reaction of the op-' positely directed diffusion-currents, the colouring will only extend over the surfaces B. In the case of optical reproduction of 'the carrier by means of transmitted light which will not be transmitted by the coloured track the luminous raysAon passing through the angularly ascending 5o edges of the protective layer I2 will be subjected to refraction which will bring about irregularities Fig. 1 is a sectional view of a carrier coming a V-shaped edge with obtuse angle of 1742' ii. A carrier is thus obtained which is shown in Fig. 2 and which simply comprises the supporting layer it and the recording layer it in which is formed the sound track 29 with the coloured walls. During the optical reproduction of this carrier refraction and consequential irregularities will not occur.

If this protective layer is constituted by a layer of Celluloid lacquer the removal may be effected for example by means of acetone or a mixture of acetone with amyl-acetate. In using these solvents care should be taken that they do not contact with the layer it of Celluloid because they also react chemically therewith. If in removing the layer of lacquer it is desired that the film should be passed through a chemical bath the said solvents are unsuitable and others will have to be selected. If the supporting layer is constituted by nitrocellulose and the covering layer by acthylcellulose use may be made of benzene or 0014. If the covering layer is made of benzylcellulose use may be made of benzene or CI-ICls. If in the examples mentioned hereinbefore the supporting layer is of acetylcellulose, benzene may be used as the solvent. If this supporting layer is coated with a protective layer of Celluloid lacquer an acetic ether will have to be used to constitute the solvent.

It is to be seen from the above that after the sound track has been cut the carrier or iilm has to be subjected to various operations. Since sound recording is effected on finite lengths of this film it is preferable that the film should be Wound on a supporting member in such manner that the sound track and the covering layer are readily accessible to the chemicals. On this member the film may be subjected to the various operations.

The choice of the covering layer and the car rier will be influenced by two factors. In the first place the protective layer will have to protect the recording layer entirely from substances which,

after the sound track has been cut, are provided for the purpose of colouring the track, a careful watch having also to be taken that the protective layer does not affect'the cutting properties of the recording layer. Secondly, the protective layer will have to be constituted by such a substance as to permit of it being chemically removed in an easy manner without attacking the subjacent recording layer.

coloured product at the surface of the track, and

thereafter removing the remaining. portions of the protective layer,

2. In the manufacture of a carrier containing a mechanically-recorded and optically-reproduce"- able vibration track, the steps comprising superimposing on a recording layer a protective layer of coloured material, mechanically removing parts of said layers to form in the recording layer a vibration track having depth and width variations, forming a coloured product at the surface of the track, and thereafter removing the remaining portions of the protective layer.

3. A method of producing a mechanically-recorded and optically-reproduceable vibration track on a carrier having a recording layer and a super--' imposed protective layer, comprising the stepsof mechanically removing parts of said layers to form in the recording layer a vibration track having depth and width variations, forming a coloured product at the surface of the track, and thereafter dissolving the remaining portions of the protective layer to remove same from the carrier.

4. A method of producing a mechanically-recorded and optically-repr'oduceable vibration track on a carrier having a recording layer and a superimposed protective layer, comprising the steps of mechanically removing parts of said layers to form in the recording layer a vibration track having depth and width variations, forming a coloured product at the surface of the track and thereafter removing the protective layer by contacting same with a surface containing a solvent for said protective layer.

5. A method of producing a mechanically-recorded and optically-reproduceable vibration track on a carrier having a recording layer and a superimposed protective layer, comprising the steps of mechanically removing parts of said layers to form in the recording layer a vibration track having depth and width variations, forming a, coloured product at the surface of the track and thereafter removing the protective layer by immersing the carrier in a solvent which dissolves the protective layer without substantially afiecting the recording layer.

6. A method of producing a mechanically-recorded and optically-reproduceable vibration track on a carrier having a recording layer and a superimposed protective layer, comprising the steps of mechanically removing parts of said layers to form in the recording layer a vibration track having depth and width variations, winding the car-- rier with interspaced turns about a supporting member, forming a coloured product at the surface of the track and thereafter removing the protective layer by immersing the wound carrier into a solvent which dissolves the protective layer without substantially afiecting the recording layer.

7. A carrier comprising a recorded layer of transparent material provided with a mechani- (rally-recorded and optically-reproduceable vibration track, said track having depth and width variations and a coloured surface, the surface of the recording layer bounding said track being exposed.

GILLES HOLST. CORNELIS JOHANNES DIPPEL. 

